Bacillus subtilis (natto) plasmid pLS20 mediates interspecies plasmid transfer

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• The plasmid pLS20 from Bacillus subtilis (natto) strain 3335 is investigated for its role in genetic exchange.
• Understanding plasmid transfer mechanisms is crucial for bacterial genetics and biotechnology.

Purpose of the Study:

• To characterize the transfer capabilities of the pLS20 plasmid.
• To explore its potential for facilitating gene transfer across different Bacillus species.

Main Methods:

• Conjugation experiments were performed using B. subtilis (natto) as a donor strain carrying pLS20.
• Plasmid transfer frequencies were quantified.
• Evidence for a conjugation-like mechanism was assessed through DNase insensitivity and filtrate experiments.
• Plasmid derivatives with selectable markers (Tn917) were generated to facilitate selection.

Main Results:

• pLS20 promoted the transfer of the tetracycline resistance plasmid pBC16 to multiple Bacillus species with varying frequencies.
• Evidence supported a plasmid-encoded, conjugation-like transfer mechanism for pLS20.
• pLS20 was demonstrated to be self-transmissible.
• pLS20 also mediated the transfer of other plasmids, including pLS19 and pUB110.
• Derivatives of pLS20 with erythromycin resistance were created for selection.

Conclusions:

• The pLS20 plasmid acts as a fertility factor, enabling the mobilization of other plasmids within and between Bacillus species.
• This system offers a novel method for introducing plasmid DNA into species that are otherwise difficult to transform.
• The development of selectable pLS20 derivatives enhances its utility for genetic manipulation in bacteria.